Walker was a supporter of the natural female form, often publicly rebuking other women for wearing makeup and heavy clothing that hid their form. Her models were never allowed to wear makeup, lipstick, or nail polish during sittings. In Invocation, considered her most detailed piece, Walker used 25 female models, all either scantly clad or nude, kneeling around three female models wearing sheer cloth[2]. Birds are depicted fluttering overhead.